JP2007298553A5 - - Google Patents

Claims (3)

An image forming unit for forming a toner image on a recording material;
An endless belt, a heater that contacts an inner surface of the endless belt, a pressure roller that forms a fixing nip portion that sandwiches and conveys a recording material that carries a toner image together with the heater via the endless belt, and a predetermined minimum size A first temperature detection element that detects the temperature of the heater in a region through which the recording material passes; a second temperature detection element that detects the temperature of the heater outside the region through which the recording material of the minimum size passes; A power control unit that controls power supplied to the heater so that the detected temperature of the first temperature detecting element maintains a target temperature, and when printing continuously on a plurality of recording materials, A fixing unit that gradually lowers the target temperature;
A conveyance control unit for controlling conveyance of the recording material;
When the detected temperature of the first temperature detecting element and the second temperature detecting element reaches a predetermined temperature difference, the transport control unit enters the preceding recording material and the subsequent recording material that enter the fixing nip portion. In an image forming apparatus that performs control to increase the interval between recording materials,
An image forming apparatus, wherein the predetermined temperature difference is set to become smaller as the number of prints during continuous printing increases. The image forming apparatus according to claim 1, wherein the apparatus has a plurality of conveyance speeds in the fixing unit, and the predetermined temperature difference is set according to a conveyance speed of the fixing unit. When the conveyance speed of the preceding recording material in the fixing unit is different from the conveyance speed of the subsequent recording material in the fixing unit, the predetermined temperature difference when the preceding recording material is conveyed by the fixing unit is determined for each conveyance. The image forming apparatus according to claim 2, wherein the image forming apparatus is set to a smaller one of the predetermined temperature differences set according to a speed.